DE102021129601A1 - Kit of parts, manufacturing process and orthodontic aid for position correction - Google Patents

Abstract

A set of parts, a manufacturing method and an orthodontic aid (1) for correcting the position of a patient's teeth (10) are proposed. The orthodontic aid (1) includes
• a body (2) with an inner flank (3), an outer flank (4) and a section (5) connecting the inner and outer flanks,
• wherein the inner flank (3) is adapted to an inner side of the teeth (10) and the outer flank (4) to an outer side of the teeth (10) in order to jointly form a respective pocket (6, 7) for each tooth (10). to form where
• the body (2) has a first stiffness in a region of a first pocket (6) and a second stiffness that differs from the first stiffness in a region of a second pocket (7).

Description

The present invention relates to a set of parts, a manufacturing method and an orthodontic aid for correcting the position of a patient's teeth. In particular, the present invention relates to an improved adaptation of orthodontic aids to the specific requirements of a patient's individual teeth.

Orthodontic aids for correcting the position of patients' teeth have long been known in the prior art. Currently particularly popular specimens are made of a transparent material or a transparent combination of materials, which can be worn in the patient's mouth in a particularly unobtrusive manner. These so-called "aligners" are offered, for example, by the company Align Technology Switzerland GmbH under the name "Invisalign". The aligners are supplied in a set of parts, whereby pairs of aligners to be worn in immediate succession (for the upper and lower jaw) differ only slightly from one another and are worn in the patient's mouth one after the other as the treatment progresses, in particular only for a few days and then exchanged for the next set of aligners. The aligners are so precisely adapted to the patient's teeth that each tooth is arranged in an individual pocket and is encompassed by the pocket over a large area and tight-fitting. In the prior art, the material thickness of the aligners is fundamentally unchangeable across the various pockets or tooth positions. This does not rule out the possibility that material thickening can occur, particularly in the area of the interdental spaces, due to the fact that strongly concave surface areas arise and, in particular, a multi-layer structure can have a greater top layer thickness.

In order to be able to carry out the targeted tooth shifts as quickly as possible and comfortably for the patient, it is advantageous to change the aligners at regular intervals. For example, the aligners can be worn by the patient for five to seven days at a time and then replaced with the next set (another pair). The present invention is based on the aforementioned technology by way of example, so that the features disclosed above—unless stated otherwise—can also be found in the invention.

The respective shape of the tooth roots can mean that certain teeth require a higher force for a certain displacement path, while other root geometries and surfaces require a different length of time or force effect to realize a corresponding displacement path. This can also be the case, for example, as a result of the reduction in the root surface, which is connected to the bone via the periodontal fibers, in the event of bone destruction by so-called periodontitis, the inflammation of the gums with subsequent bone loss.

It is an object of the present invention to satisfy the need identified above and in this respect in particular to record the change interval of the aligners or to realize an identical wearing time for each set of aligners.

The object identified above is achieved according to the invention by an orthodontic aid for correcting the position of a patient's teeth with the features of claim 1 and by a manufacturing method for such an orthodontic aid with the features of claim 7 and a parts set with the features of claim 10. The dependent claims show preferred developments of the invention.

The orthodontic aid is used to correct the position of a patient's teeth and could also be referred to as a brace, aligner or splint. It is preferably worn by the patient for several hours, extremely preferably almost full-time, and is only removed from the mouth to take food and drinks (especially if pigmented). It has a body with an inner flank and an outer flank. The inner flank could be referred to as the flank facing the tongue or pharynx, while the outer flank faces the opposite, mating convex surface of the teeth facing the patient's lips. The inner flank and the outer flank of the body are held together by a connecting section in the area of the occlusal surfaces of the teeth. The inner flank, the outer flank and the connecting section are adapted to the tooth surface in such a way that they form a pocket (in particular not closed with respect to adjacent pockets) for each tooth. In this case, the pockets can have concave additional structures in order to accommodate “attachments” or attachments that are optionally attached to the patient's teeth in order to produce a form fit. According to the invention, the body has a first stiffness in a region of a first pocket and a second stiffness that differs from the first stiffness in a region of a second pocket. In other words, the body is, for example, adapted to the patient's dentition in terms of its rigidity in such a way that a first tooth, which is used to correct the position via the Tra period of time the orthodontic aid requires a higher force, is arranged in an area of a first pocket, which generates a higher average force for the position correction over the wearing period and a second tooth, which requires a lower force for the position correction over the same period, in one Area of a second pocket is arranged, which generates a lower average force for the position correction over the same wearing period. Therefore, the first rigidity or the second rigidity could also be understood as the "respective prestressing" of the orthodontic aid relative to the tooth surface, so that a corresponding prestressing of the respective pockets relative to the tooth is achieved depending on the force requirement. The wearing period of a respective set of aligners can thus be kept the same, although the tooth to be moved in each case requires a specific force which results, for example, from the root geometry, the root surface or the root length of the respective tooth. In particular, programs for reminding the patient to change the orthodontic appliance set are simplified. In addition, it can be avoided that unnecessarily high forces are exerted on teeth that require a comparatively low force in order to realize a distance to be covered during the wearing period. As a result, the wearing comfort can be increased for the patient by adjusting the rigidity and the corrective force, which increases the patient's acceptance of the orthodontic aid. Furthermore, through targeted thickening of the material layer thickness of an area that goes under in relation to the direction of insertion, attachments can also be dispensed with, since the direction of force and effect on the tooth can thus be better defined.

The different rigidities can be generated by different material thicknesses in a predefined manner. In other words, a thicker wall of the inner flank and/or the outer flank and/or the connecting section can be selected in such a way that the respective rigidity corresponds to the purpose of the treatment. Different material thicknesses can be realized, for example, in the course of production and make the use of different materials for the orthodontic aid unnecessary. This can make the production cheap.

• • Sicherheitsdatenblatt mit der Überschrift „KeySplint Soft“, Ausgabedatum/Überarbeitungsdatum: 11/14/2019, Version: 1. Die in dem vorgenannten Sicherheitsdatenblatt genannten Produktcodes sind 4220005 sowie 4200005 und bei ordnungsgemäßer Anwendung für die Herstellung kieferorthopädischer Hilfsmittel geeignet und erfolgreich erprobt.
• • Sicherheitsdatenblatt mit der Überschrift „KeyOrtholBT Bulk“, Ausgabedatum/Überarbeitungsdatum: 10/28/2020, Version: 1. Der in dem vorgenannten Sicherheitsdatenblatt genannte Produktcode 4210008 ist bei ordnungsgemäßer Anwendung für die Herstellung kieferorthopädischer Hilfsmittel geeignet und erfolgreich erprobt.

Materials that can be used in the context of the present invention can be, for example, those that are mentioned in the following safety data sheets from Keystone Industries:

• • Material Safety Data Sheet entitled "KeySplint Soft", Issue Date/Revision Date: 11/14/2019, Version: 1. The product codes mentioned in the aforementioned Material Safety Data Sheet are 4220005 and 4200005 and, when used properly, are suitable and successfully tested for the manufacture of orthodontic appliances.
• • Material Safety Data Sheet entitled "KeyOrtholBT Bulk", Issue Date/Revision Date: 10/28/2020, Version: 1. The product code 4210008 mentioned in the aforementioned material safety data sheet is suitable and successfully tested for the production of orthodontic appliances when used properly.

Other materials that can be used alternatively or additionally are Graphy Tera resin TC-850DAC or DPW.

The body can be made of plastic or have a body blank made of plastic, which is milled and/or cast from a piece of plastic, for example, or made of a metal used only in the undercut area under the tooth equator, especially in the lower jaw, e.g. NiTiNol with superelastic properties. Additive manufacturing of the body blank in the manner of 3D printing is also possible. The body blank can then be coated with a top layer, which adapts the body blank to the requirements of the patient's mouth. For example, the body blank can then be sprayed, wetted or immersed in a hardened plastic. The different rigidities and/or material thicknesses can now be realized both through the body blank and alternatively or additionally through the cover layer. This can result in the body blank having a lower thickness at the relevant point than at other positions on the body. Alternatively or additionally, the cover layer can be thinner at this position than at other positions. This does not preclude the total thickness of the body in the area of the first pocket being essentially identical to that of the second pocket or having differences in the layer thicknesses in the different areas or adapted to the direction of movement. In other words, the thicknesses of the body blank and the cover layer can compensate for one another, while the different stiffnesses according to the invention are realized in the respective combination. This can increase the wearing comfort for patients and in particular keep the volume of the orthodontic aid homogeneous and low.

Alternatively or additionally, the first rigidity can differ from the second rigidity in that a first th material is used, while a second material is used in the area of the second pocket. This first and second material can be used in particular as part of the body blank. Alternatively or additionally, the first material can be used for the cover layer in the area of the first pocket and the second material can be used in the area of the second pocket. This does not preclude the use of different materials for both the body blank and the cover layer in the area of the first pocket than for the body blank and the cover layer in the area of the second till. In particular, the first material and the second material have different elasticities or stiffnesses, resulting in different restoring forces or prestresses in relation to the tooth surface. The material thickness of the orthodontic aid in the area of the first pocket and in the area of the second pocket can thus be kept essentially identical, although different rigidities are implemented. This increases the wearing comfort and can reduce the volume of the orthodontic aid.

Optionally, the first material may not be included in the area of the second pocket. For example, the cover layer can be completely omitted in the area of the second pocket. Generally speaking, with a different choice of material, a material can be used in the area of the first pocket that does not occur at all in the area of the second pocket (or vice versa). The rigidity can thus be flexibly adjusted without having to vary the thickness (wall thickness) of the orthodontic aid excessively.

The orthodontic aid is usually made after a scan and/or an X-ray of the patient's dentition. Data on the tooth geometry, the tooth root geometry and the tooth root surface/tooth root length are therefore available anyway. With the appropriate 3D X-ray methods, the active root surfaces can also be individually mapped and thus measured very precisely. Experience has shown that the tooth roots are primarily responsible for those forces that are required to move a tooth over a certain distance (or through a certain angle) in a certain period of time. The larger the tooth surface transverse to the direction of movement, the greater the force required to move the tooth a given distance. The geometries of the tooth root surface are also decisive for rotations and must be taken into account compared to the pure volume of the tooth root. Therefore, on the basis of the scans or X-rays, statements can be made about the stiffness of the pockets or splints in the area of the undercut areas in the area of the respective teeth in order to keep the change interval of the sets of orthodontic aids constant over time or to be kept constant over the respective sets.

According to a second aspect of the present invention, a manufacturing method for an orthodontic aid to be worn in a patient's mouth for correcting the position of a patient's teeth is proposed. The manufacturing method can result in an orthodontic aid according to the first-mentioned aspect of the invention. In a first step, a first tooth root geometry and/or a first tooth root surface and/or a first tooth root length of a first tooth is determined. This can be done, for example, by a scan and/or an X-ray of the patient's dentition. The tooth can also be identified automatically and the root geometry can be determined using a predefined reference. For example, a visible surface of the tooth can provide information about the size or shape of the root of the tooth. In a second step, a second tooth root geometry and/or a second root surface and/or a second tooth root length of a second tooth is determined. This can also be done by scanning and/or x-ray, for example according to the method used in connection with the first tooth. In particular, a digitally represented recording of the tooth root is the starting point for a computer-assisted determination of the tooth root geometry, surface and/or length. Depending on the aforementioned data, a first stiffness is then (in particular automatically) assigned to a region of a first pocket of a body of the orthodontic aid for the first tooth. In other words, it is determined that, based on the aforementioned data, the rigidity of the orthodontic aid should have a first variable in the area of the first tooth. Similarly, a second stiffness is automatically associated with a second pocket portion of the orthodontic appliance body for the second tooth. In this case, the second rigidity is automatically selected differently from the first rigidity, depending on the above information, in order to harmonize the speed at which the tooth is displaced in the patient's jaw. For this purpose, in a last step, the body of the orthodontic aid is manufactured with the first rigidity in the area of the first pocket and with the second rigidity in the area of the second pocket. As explained above, there are different ways of varying the first stiffness compared to the second stiffness (e.g. material and/or material thickness and/or material combinations etc.).

In particular, within the framework of a computer program, a database based on a 3D scan and/or based on a 3D X-ray of a patient's dentition can be parameterized for automatic production of the orthodontic aid in such a way that the rigidities are automatically calculated in a predefined relationship to the tooth root geometry, surface and/or or length can be selected. In particular, therefore, no interposition of human intellectual activity is required in order to define or propose the shape and/or the properties of the orthodontic aid from a digital image or a digital representation of a patient's teeth. For example, the manufacturing thickness of the body blank can be defined automatically using the data in a CNC milling process. Alternatively or additionally, the material thickness and/or material selection for a 3D printing process can be automatically defined based on the data. Alternatively or additionally, a certain number of layers and/or an adapted layer thickness can be defined automatically for the cover layer in the area of the first pocket based on the data.

Thus, in particular, the same advantages, combinations of features and features result for the manufacturing method proposed according to the invention as have been explained in connection with the first-mentioned aspect of the invention of the orthodontic aid.

According to a third aspect of the present invention, a set of parts is proposed which has at least two orthodontic appliances (e.g. two pairs of aligners) for correcting the position of a patient's teeth according to the first aspect. The two orthodontic aids must be worn consecutively in the course of therapy. For example, they can be assigned to a lower jaw of the patient or to an upper jaw of the patient. While the two orthodontic appliances of the kit are both embodied in accordance with the above aspects of the present invention, they nevertheless differ, at least optionally, in that they address movement of different teeth. For example, for a treatment period during which the first orthodontic aid is to be worn, the intention is to move a first tooth, while for a treatment period which follows sequentially in time, the intention is to move a second tooth, e.g. a tooth adjacent to the first tooth. In particular in the event that the two teeth have different tooth root geometries and/or tooth root surfaces and/or tooth root lengths, a respective stiffness in the area of the respective pockets for the two teeth can be adjusted according to the invention by using different thicknesses and/or different materials in the area of the respective bags are used. In particular, if the two orthodontic aids in the kit intend to move one and the same tooth, the rigidity of the two first pockets can be identical and the rigidity of their second pocket can also be identical to one another. The entire set of parts can thus be designed in accordance with the invention, although for a set of orthodontic aids under consideration the respective first pocket and the respective second pocket are arranged at a different position in the oral cavity of the patient than for a set of orthodontic aids other than the set under consideration. In other words, the first pocket of a first set of orthodontic appliances can be associated with a first tooth of the patient, while the first pocket of a second set of orthodontic appliances can be associated with a second tooth of the patient. The mutually different rigidities of the pockets can thus migrate, so to speak, in the course of the treatment of the patient, depending on the treatment section and the tooth root geometry. In addition, through targeted hollowing within the pockets, the force effect of a stiffened opposite side can also determine the tooth movement direction, which biomechanically usually corresponds to a certain pendulum movement.

• 1 eine perspektivische Darstellung eines kieferorthopädischen Hilfsmittels gemäß einem ersten Ausführungsbeispiel der vorliegenden Erfindung; und
• 2 ein Flussdiagramm veranschaulichend Schritte eines Ausführungsbeispiels eines erfindungsgemäßen Herstellungsverfahrens für ein kieferorthopädisches Hilfsmittel.

Further details, advantages and features of the present invention result from the following description of exemplary embodiments with reference to the drawing. Show it:

• 1 a perspective view of an orthodontic aid according to a first embodiment of the present invention; and
• 2 a flow chart illustrating steps of an embodiment of a manufacturing method according to the invention for an orthodontic aid.

1 shows an orthodontic aid 1 in the form of an aligner for a lower jaw of a patient. The lower jaw has teeth 10 which are arranged in respective pockets 6 , 7 of the body 2 . The respective pockets 6, 7 are formed by an inner flank 3, an outer flank 4 and a section 5 connecting the inner and outer flanks 3, 4. The body 2 is transparent so that the teeth 10 shine through the orthodontic aid 1 to. The orthodontic aid 1 only covers the surface areas of the teeth 10 protruding or exposed from the gums of the patient. However, the roots 8 of the teeth 10 are also shown for illustration, with different geometries and lengths of the roots 8 being recognizable and being able to be recorded using data technology. To achieve different rigidities of the orthodontic aid 1 , a first area in the area of a pocket 7 has a different material than a second pocket 6 . It has a higher rigidity because the tooth root has a length and surface area that is well above average and the tooth therefore requires an above-average force in order to cover a certain distance in relation to the jaw during the course of treatment. Thus, due to the material of higher rigidity, a stronger force is exerted on the tooth within the pocket 7 and, despite the same wearing time, a subsequent (not shown) orthodontic aid can intend to shift an adjacent tooth, so that delays in the course of treatment or unequally long treatment times of the individual teeth can be avoided. This increases the patient's acceptance of the orthodontic aid 1 and can increase wearing comfort, particularly in the area of teeth that have a small tooth root surface or tooth root length.

2 shows steps of an embodiment of a manufacturing method according to the invention for manufacturing an orthodontic aid 1, as shown in 1 is shown. In step 100, a first tooth root geometry of a first tooth of a patient is determined. This is done by digitally evaluating an X-ray of the patient's dentition. The data is then automatically examined to determine how much force the first tooth in question will exert on the orthodontic aid or how much force is required to move the first tooth by a predefined path or a predefined angle. The same is done in step 200 for a second tooth and subsequently for all other teeth of the patient. Depending on the first tooth root geometry and the second tooth root geometry, in step 300 a first stiffness is assigned to an area of a first pocket of the orthodontic device and in step 400 a second stiffness is assigned to an area of a second pocket of the orthodontic device. This can include parameterizing a 3D printer and/or a computer-guided milling process. In step 500, the body is manufactured with the first stiffness in the area of the first pocket and the second stiffness in the area of the second pocket. A raw body can be created and then covered with a top layer.

As a result, the acceptance of orthodontic aids for the patient is increased, the change interval from one set to the next set of the orthodontic aid is homogenized and the acceptance of the orthodontic aid by the patient is increased.

In addition to the above written description of the invention, reference is hereby explicitly made to the graphic representation of the invention in FIGS 1 and 2 referenced.

Reference List

1

orthodontic aid

2

body

3

inner flank

4

outer flank

5

connecting section

6, 7

Bag

8th

tooth root

10

Tooth

100 to 500

process steps

Claims (10)

Orthodontic aid (1) for correcting the position of a patient's teeth (10). • a body (2) with an inner flank (3), an outer flank (4) and a section (5) connecting the inner and outer flanks, • wherein the inner flank (3) is adapted to an inner side of the teeth (10) and the outer flank (4) to an outer side of the teeth (10) in order to jointly form a respective pocket (6, 7) for each tooth (10). to form where • the body (2) has a first stiffness in a region of a first pocket (6) and a second stiffness that differs from the first stiffness in a region of a second pocket (7). Orthodontic aids claim 1 , where the first and the second rigidity are generated by different material thicknesses. Orthodontic aids claim 2 , wherein the body (2) comprises a body blank milled from a plastic or additively manufactured, which is coated in particular with a cover layer, the different rigidities and/or material thicknesses being realized by the body blank and/or the cover layer . Orthodontic device according to one of the preceding claims, wherein the first and the second stiffness by - A use of a first material in the region of the first pocket (6) and - A use of a second material in the area of the second pocket (7) can be produced. Orthodontic appliance according to one of the preceding claims, in which the first material is not contained in the region of the second pocket (6). Orthodontic aid according to one of the preceding claims, wherein the first stiffness and/or the second stiffness is selected automatically depending on a tooth root surface and/or a tooth root length of a respective tooth (10) for which the pockets (6, 7) are provided. Manufacturing method for an orthodontic aid (1) for correcting the position of a patient's teeth, comprising the steps: - determining (100) a first tooth root geometry and/or tooth root surface and/or a tooth root length of a first tooth (10) of the patient, - determining (200) a second tooth root geometry and/or tooth root surface and/or a tooth root length of a second tooth (10) of the patient, depending on the first and second tooth root geometry and/or tooth root surface and/or a tooth root length - Assigning (300) a first rigidity to an area of a first pocket (6) of a body (2) of the orthodontic aid (1) for the first tooth (10) and - Assigning (400) a second stiffness, which differs from the first stiffness, to an area of a second pocket of the body of the orthodontic aid (1) for the second tooth (10) and - Manufacture (500) of the body (2) with the first rigidity in the area of the first pocket (6) and the second rigidity in the area of the second pocket (7). manufacturing process claim 7 , wherein - the assignment of the first stiffness to the area of the first pocket (6) of the body for the first tooth (10) predefines a first material thickness and - the assignment of the second stiffness to the area of the second pocket (7) of the body 'For the second tooth (10) includes a predefining of a second, different from the first material thickness, material thickness. manufacturing process claim 7 or 8th , wherein - the assignment of the first stiffness to the area of the first pocket (6) of the body (10) for the first tooth (10) predefines a first material and - the assignment of the second stiffness to the area of the second pocket (7 ) of the body for the second tooth (10) includes predefining a second material that is different from the first material. Parts set comprising at least two orthodontic aids (1) for correcting the position of a patient's teeth (10) according to one of Claims 1 until 6 , wherein - the body (2) of a first orthodontic aid (1) has the first stiffness in the area of its first pocket (6) and - the body (2) of a second orthodontic aid (1) in the area of its first pocket (6 ) has the first stiffness, the first stiffness of the second orthodontic device (1) being identical to or different from the first stiffness of the first orthodontic device (1).

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